[ENet-discuss] Long Distance Packet Loss (maybe)?

[Alex Milstead]

On 1/15/2010 12:25 PM, Lee Salzman wrote:
> enet_host_flush just sends the packet only once. If the packet gets 
> lost, enet_host_service ensures it gets resent until it is delivered.
>
> Lee
>
> Alex Milstead wrote:
>> On 1/15/2010 11:28 AM, Lee Salzman wrote:
>>> Are you regularly calling enet_host_service on the client?
>>>
>>> Lee
>>>
>>> Alex Milstead wrote:
>>>> Hey all,
>>>>
>>>> Just a heads up, (I don't know how reliable this is, exactly, but) 
>>>> I've been using a network packet monitoring tool call "wireshark" 
>>>> to monitor packets coming back and forth between client and server 
>>>> apps using an ENet wrapper I wrote.
>>>>
>>>> I'm using ENet to send a struct back and forth between machines. 
>>>> The struct itself isn't very big (only about 10 fields inside), and 
>>>> for the longest time sending it to and fro was no big problem. 
>>>> Recently, though, I've been testing out the server piece of the 
>>>> app(s) I'm writing, and according to wireshark, I'm receiving 
>>>> "Malformed Packets". I see this happening pretty frequently between 
>>>> machines when the client and server are in the same general 
>>>> (geographical) locale, however I've got a team member that is 
>>>> testing the client from Oregon (I'm in Georgia), and some seriously 
>>>> screwed up is happening. Every time he sends data, wireshark picks 
>>>> up that a packet is coming in, but ENet -never- hits the 
>>>> "ENET_EVENT_TYPE_RECEIVE" event on the server host that is 
>>>> servicing the connection.
>>>>
>>>> The basic break down of the apps ENet protocols are as follows 
>>>> (sans the client connecting to the server for the first time):
>>>>
>>>> Client code:
>>>> ...
>>>>
>>>> SendData(void *data)
>>>> {
>>>>    if (connected) // flag set to true when enet_host_connect and 
>>>> subsequent (enet_host_service && event.type == 
>>>> ENET_EVENT_TYPE_CONNECT) events are true
>>>>       ENetPacket *packet = enet_packet_create(struct_ref, 
>>>> sizeof(structReferenced), ENET_PACKET_FLAG_RELIABLE);
>>>>       enet_peer_send(server, channel, packet);
>>>>       enet_host_flush(connection);
>>>> }
>>>> ...
>>>>
>>>> Server Code:
>>>> ...
>>>> while (enet_host_service(connection, &event, connection_lifetime) 
>>>> >= 0 && !quit) {
>>>>        switch (event.type) {
>>>>            case ENET_EVENT_TYPE_CONNECT:
>>>>                cout << "A new client connected!";
>>>>
>>>>                break;
>>>>            case ENET_EVENT_TYPE_RECEIVE:
>>>>                ProcessPacket(event);
>>>>                break;
>>>>       }
>>>> }
>>>> ...
>>>>
>>>> The problem appears to be when packets are sent from the client 
>>>> machine in Oregon. Like I mentioned, wireshark is telling me that 
>>>> the packet actually made it, but the ENET_EVENT_TYPE_RECEIVE 
>>>> -never- occurs. Again, I'm not sure how reliable "wireshark" is, 
>>>> but it's telling me that the UDP packet being sent is "malformed". 
>>>> This doesn't seem to happen when I'm sending from a client machine 
>>>> that is geographically closer to the server (e.g. in my home, but 
>>>> sending requests to the frontal IP instead of a local IP), although 
>>>> wireshark still seems to report that the datagram sent from the 
>>>> closer machine is also sometimes "malformed".
>>>>
>>>>
>>>> Any ideas on what's happening/going wrong?
>>>>
>>>> Thanks for any help in advance.
>>>>
>>>> Cheers,
>>>> Alex
>>>>
>>> _______________________________________________
>>> ENet-discuss mailing list
>>> ENet-discuss at cubik.org
>>> http://lists.cubik.org/mailman/listinfo/enet-discuss
>> Yes. The method which calls "SendData", immediately calls 
>> enet_host_service afterward to listen for response packets from the 
>> server.
>>
>> Should I be using "enet_host_service(conn, &event, lifetime) && 
>> event.type == ENET_EVENT_TYPE_CONNECT" before sending a packet? I 
>> thought the purpose of enet_flush_host was to send off packets 
>> without having to service the host.
>> _______________________________________________
>> ENet-discuss mailing list
>> ENet-discuss at cubik.org
>> http://lists.cubik.org/mailman/listinfo/enet-discuss
>>
>
> _______________________________________________
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> http://lists.cubik.org/mailman/listinfo/enet-discuss
Well I'll try using enet_host_service and see if that helps any. Is 
there any explanation for wireshark reporting "malformed packets"? 
Again, I'm not sure if wireshark is the right monitoring tool for 
inspecting ENet packets, but it seems to be pretty standard across the web.

Is there any packet monitoring tool that you would suggest?